Fluid filter with a central component which can be assembled

ABSTRACT

The invention relates to a fluid filter, such as an oil filter for an internal combustion engine, comprising a filter housing which can be closed by a screw lid, a filter element and a central, approximately tubular component which projects into the interior of the filter, whereby the central component has bearing surfaces which are used to fix said component into the filter, so that it cannot rotate. The central component and the filter housing have projections and corresponding undercuts which interact with the projections, in order to fix the central component using a detent or snap-fit connection. The invention is characterized in that the lid, the filter element and the central component can be connected to form a joint installation assembly which is easy to handle, whereby the central component is mounted so that it can be rotated about its longitudinal axis in relation to the lid and that guide elements are provided in the filter housing which interact with the bearing surfaces, in such a way that the latter form of rotational lock for the central component during the mounting of the installation assembly, before the central component is fixed by the detent or snap-fit connection, thus allowing said connection to take place.

BACKGROUND OF THE INVENTION

The present invention relates to a fluid filter suitable for use in aninternal combustion engine.

Conventional fluid filters are described in German Utility ModelApplication 299 15 841.1.

The central component is made somewhat tubular. “Somewhat tubular” meansthat a closed tube need not be provided but the central component canhave openings and form a supporting mandrel known of itself or a drainmandrel likewise known of itself or a filter bypass valve likewise knownof itself. In particular, provision can be made to make the centralcomponent in the shape of a combination component both as a supportingmandrel and as a drain mandrel and/or filter bypass valve.

The filter housing can be molded fixedly onto a motor housing part, castfor example, so that assembly of the filter takes place in an automobilefactory for example with the filter housing provided on the motor beingfitted with the remaining components of the filter supplied.

Simple and rapid assembly of the central component can be provided bymeans of a latching or snapping connection, with one or more projectionsor recesses being provided on the filter housing itself or on acomponent connected with the filter housing, and provided with one ormore corresponding recesses or projections on the central component. Inorder to achieve good spring elasticity during latching, the projectionsand/or undercuts cannot extend around the entire circumference of thecentral component but only around portions of this circumference.

A rotation-resistant mounting of the central component that preventsmovement around the lengthwise axis of this component ensures thatlatching between the central component in the filter housing is retainedand the central component does not undesirably come loose from thefilter housing. This rotation blocker can be ensured for example by anadditional valve body which can be mounted off-center on the centralcomponent itself.

SUMMARY OF THE INVENTION

The goal of the present invention is to provide an improved filter thatis economical and can be mounted quickly.

In other words, the invention proposes making a first jointly manageableassembly which comprises the lid, the filter insert, and the centralcomponent. Such a uniformly manageable assembly can be inserted simply,economically, and rapidly by machine into the filter housing. The entireinstallation group is rotated to screw down the lid. The centralcomponent is likewise rotationally driven by the fact that itsconnection with the filter insert and/or with the lid permits thetransfer of certain rotational moments, for example by a clamping forcebetween the connected parts or by connecting ribs that break if certainrotational moments are exceeded, or the like.

It is provided that, during the assembly process, the central componenthas its contact surfaces against or on the corresponding projections ofthe filter housing. The resulting rotational movement which the centralcomponent executes together with the lid ensures that the centralcomponent reaches the desired rotational position from any initialrotational position in which the central component is aligned in adefinite position in terms of its rotational angular position whichfirstly ensures secure latching with the filter housing and also ensuresthat the central component is aligned in this latching position to formthe desired rotational latch.

For this purpose, the central component is mounted rotatably relative tothe lid around its lengthwise axis, for example by overcoming theabove-mentioned clamping forces by breaking the aforementionedconnecting ribs or the like. Provision can be made such that the centralcomponent is held directly on the lid or on the filter insert, whereuponthe central component is mounted rotatably relative to the filter insertand/or the latter is mounted rotatably relative to the lid. In thismanner a screwing movement for the lid is made possible with which it isscrewed into the filter housing while at the same time the centralcomponent, resting against the projection on the filter housing side,retains its rotational angular position and does not rotate with it anyfurther.

According to the invention, guide means are provided internally on thefilter housing which serve to prevent rotation during assembly and whichcooperate with the contact surfaces of the central component. Theseguide means ensure the correct rotational angular position of thecentral component during further assembly. During an additional screwingprocess of the lid, the central component therefore remains in itsoptimum rotational angular position and is merely introducedincreasingly further into the filter housing because of the screwingprocess until the central component and the filter housing latch.

The projections which perform the rotational lock during assembly bycooperating with the contact surfaces of the central component can beformed by a nose or strip that projects into the interior of the filterhousing, but the projection can also be formed by the side of a groovewhen the contact surface of the central component extends into thisgroove.

Advantageously, the rotational lock effective during operation andprovided in any case, in addition to its actual goal of preventinginadvertent loosening of the central component from the filter housingwhile the filter is operating, can also be used to create anintroduction aid or rotational lock during the assembly of the centralcomponent.

For this purpose, a projection provided on the filter housing side canbe provided not only in the raised position of the filter housing inwhich it cooperates in the operating state of the filter with thecorresponding contact surfaces of the central component. Instead, thisprojection on the filter housing side can be extended to the lid openingof the filter housing since the central component is usually inserted bythis opening.

This extension of the projection can be made economically and alsopermits early contact between the contact surfaces on the centralcomponent on the one hand and the projection on the filter housing onthe other hand so that the central component is reliably guided into thedesired position during its assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will be described in detail below withreference to the drawings.

FIG. 1 shows an installation group for a fluid filter;

FIG. 2 shows a closed filter in its usual operating state with themounted installation group;

FIG. 3 shows the partially opened filter of FIG. 2 in which the lid ispartially unscrewed; and

FIGS. 4 and 5 each show a section through the filter in FIG. 2 alonglines A—A, initially during the assembly of the filter and with thefilter in the final assembled state.

DESCRIPTION OF ILLUSTRATED EMBODIMENT

In FIG. 2, reference numeral 1 generally designates a filter with afilter housing 2, a lid 3, and a replaceable filter insert 4. The filter1 shown is provided as an oil filter for an internal combustion engine.It has an inlet 5 for clean filtered oil and a drain line 7 which isclosed in FIG. 2 and can be drained from the interior of the filter onlywhen changing filters, in other words when changing filter insert 4,without this drained oil being mixed with the clean oil since there isno connection 2 to outlet 6.

A central component 8 designed as a drain mandrel is provided in filter1. Central component 8 has a spring claw 9 at its lower end which holdscentral component 8 against the action of a spring 10 by abutting aprojection 11 provided in outlet 6. Spring claw 9 and projection 11 formprojections and undercuts which cooperate with one another alternately.They also ensure reliable retention of central component 8 with veryhigh forces of spring 10.

In particular, it is clear from FIG. 3 that, with lid 3 alreadypartially unscrewed, spring 10 lifts central component 8 until thiscomponent 8 is held only by the latching or snapping connection betweenspring claw 9 and projection 11. In this raised state of the drainmandrel there is a connection between the filter interior and drain line7 so that oil in filter 1 is drained off through drain line 7 before lid3 is completely unscrewed. In this way, low-contamination removal offilter insert 4 is made possible.

Central component 8 is designed as a combination component. On the onehand it forms the above-mentioned drain mandrel. In addition, it haslengthwise ribs 12 with which it extends into the interior of filterinsert 4. In this area, lengthwise ribs 12 have a plurality ofhorizontal ribs 14 so that the central component 8 in this area forms asupporting mandrel for filter insert 4. In addition, central component 8has a filter bypass valve 15 as well as a return-blocking valve 17 on alaterally projecting plate 16 with a plate-shaped valve body 22.

On the inside wall of filter housing 2, as is clear in particular fromFIGS. 4 and 5, two shaped projections 18 a and 18 b are provided,designed as strips running lengthwise of filter 1. Central component 8has a shaped nose 21 whose side edges form contact surfaces 20 by whichcentral component 8 abuts projections 18 so that, as FIG. 5 shows,rotational movement of central component 8 around its lengthwise axis isprohibited when component 8 is in the mounted state.

It is clear from FIGS. 1 to 3 that projection 11 is formed by acorresponding undercut in the wall of outlet 6 as a circumferential ribwhile spring claw 9 is provided only along a limited angular rangearound the circumference of central component 8 to permit good springmobility. Regardless of the angular position of central component 8, itis therefore held securely in filter housing 2 as soon as centralcomponent 8 has been inserted deep enough into filter housing 2 andspring claw 9 has gripped behind projection 11. Instead of the onespring claw 9 shown, two or more spring claws 9 can be provided toensure an especially secure seat for central component 8 in filterhousing 2.

It is clear from FIG. 1 that there is an installation group 23comprising lid 3, filter insert 4, and central component 8. An upper enddisk 24 of filter insert 4 is connected releasably with lid 3 by aplurality of spring hooks 25. On the one hand, the contour of lid 3 andspring hooks 25 permits rotational mobility of filter insert 4 withinlid 3; on the other hand, the clamping force of spring hooks 25 ensuresup to a certain resistance that the filter insert 4 can be rotatedtogether with lid 3.

The upper end disk 24 also has one or more matching hooks 26 extendinginto the interior of filter insert 4 which fit behind the uppermost ofribs 14 and thereby hold central component 8 and filter insert 4. Thisprovides a nonrotating connection between filter insert 4 and centralcomponent 8. For this purpose wings are provided on central component 8which extend radially outside filter bypass valve 15 to uppermost rib 14and form a stop for matching hooks 26.

A spring 27 of filter bypass valve 15 is relaxed in the state ofinstallation group 23 shown in FIG. 1 or, in contrast to the embodimentsshown, provision can also be made such that the valve mushroom of filterbypass valve 15 does not abut the associated valve seat of upper enddisk 24 in order in this way to ensure a good rotational mobility ofcentral component 8 which carries this valve mushroom relative to filterinsert 4.

During installation, entire installation group 23 is held against lid 3by a screwing tool and introduced into filter housing 2. Centralcomponent 8 is the first to enter filter housing 2. The screwing tool ofinstallation group 23 performs a continuous rotational movement in thisposition so that, by means of the clamping force, a spring hook 25 issupported by the net weight of the individual components of installationgroup 23 and is rotated by the non-rotational arrangement of latchinghooks 26 on central component 8, as are filter insert 4 and centralcomponent 8 together with lid 3 around its lengthwise axis.

FIG. 4 shows purely as an example how central component 8 can be alignedwithin filter housing 2. The rotational movement of the lid in whichcentral component 8 is entrained clockwise can initially take placewithout impediment. Looking in the axial direction of filter 1, of thetwo projections 18, projection 18 b shown at the bottom in FIGS. 4 and 5is higher in filter housing 2, in other words closer to lid 3 thanprojection 18 a shown at the top in FIGS. 4 and 5. During the rotationalmovement of lid 3 and the resultant rotational movement of centralcomponent 8, this means that contact surface 20 in the front in therotational direction presses against projection 18 b when centralcomponent 8 is in the rotational angular position according to FIG. 5.

The further rotational movement caused by the screwing tool causes lid 3to be screwed increasingly into filter housing 2. The fact that centralcomponent 8 is mounted rotationally movably relative to lid 3 allowsrelative movement between these two parts of installation group 23 sothat central component 8 remains in its rotational angular positionshown in FIG. 5 and is simply moved axially further by the furtherscrewing of lid 3 and is thereby introduced to a greater depth intofilter housing 2. In the rotational angular position of centralcomponent 8 shown in FIG. 5, projection 11 can cooperate with springclaw 9 of central component 8 in outlet 6 of filter housing 2 so that,when a corresponding screwing depth of installation group 23 is reachedas shown in FIG. 3, a latching connection between central component 8and filter housing 2 is created.

This is followed by additional automatic screwing until lid 3, as shownin FIG. 2, is screwed completely into filter housing 2.

When the filter is exchanged later, lid 3 is unscrewed again from itsoperating position shown in FIG. 2. When it has reached the positionshown in FIG. 3, the oil remaining inside the filter can be drained offthrough drain line 7. At the same time, central component 8 is held infilter housing 2 by the latching function of spring claw 9 andprojection 11. Unscrewing lid 3 causes the comparatively much weakerlatch between central component 8 and filter insert 4 to be released sothat lid 3 together with filter insert 4 can be removed from the filterwhile central component 8 remains integral with the filter, in otherwords on filter housing 2.

When a new filter insert 4 is inserted, provision can be made to createspecial material-saving replacement filter inserts in which upper enddisk 24 is not provided with latching hooks 26. With smaller quantities,such a differentiation of the filter inserts can be economically avoidedand an exchange filter insert with such latching hooks 26 can beprovided.

FIG. 1 schematically indicates spacing ribs 28 of which one or more areprovided on lid 3 and/or one or more are provided on filter insert 4.These spacing ribs 28 serve to secure filter insert 4 from tiltingmovements within lid 3. They can be provided with a corresponding radialoverlap in the form of dogs that cooperate with one another in order toensure a rotary entrainment of filter insert 4 when lid 3 is rotated bythe screwing tool. At the beginning of assembly, the rotary movement oflid 3 can be transferred to central component 8 fastened to filterinsert 4 so that the latter has its contact surfaces 20 securely againstprojection 18 b. Such dogs could permit higher rotational forces bycomparison with filter hooks 25 and make it possible to use weakerspring hooks 25 that facilitate removal of filter insert 4 from lid 3when changing the filter.

What is claimed is:
 1. A fluid filter comprising a filter housing havinga lid opening closable by a lid, a filter insert and a central componentextending into an interior of the filter housing, said central componentincludes contact surfaces to hold said central component nonrotatably inthe filter housing, and wherein the central component is held to thefilter housing by a latching or snapping connection, wherein the lid,the filter insert, and the central component are adapted to be connectedtogether to form a jointly manageable installation group, with thecentral component being rotatably mounted relative to the lid around alengthwise axis, and guide means being provided internally on the filterhousing for cooperating with the contact surfaces in such a way to holdsaid central component nonrotatably in the filter housing duringassembly of the installation group with the filter housing before thecentral component is secured to said filter housing by means of thelatching or snapping connection.
 2. Filter according to claim 1, whereinthe guide means includes a projection that is extended towards said lidopening.
 3. Filter according to claim 1, wherein the central componentis releasably connected to the filter insert.
 4. Filter according toclaim 3, wherein the central component is rotationally movably connectedto the filter insert.
 5. Filter according to claim 3, wherein thecentral component is non-rotationally movably connected to the filterinsert.
 6. Filter according to claim 1, wherein the lid is rotationallymovably connected to the filter insert.
 7. Filter according to claim 1,wherein the central component comprises a drain mandrel.
 8. Filteraccording to claim 1, wherein the central component comprises asupporting mandrel.